st: RE: Matrices utilities, Basic calculations. When to start using Mata over Stata?‏

st: RE: Matrices utilities, Basic calculations. When to start using Mata over Stata?‏

Date

Fri, 23 Apr 2010 14:09:07 +0200

You could perhaps use svmat and then egen rowtotal?
Abhimanyu
-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Radaf paf
Sent: vrijdag 23 april 2010 13:50
To: statalist@hsphsun2.harvard.edu
Subject: st: Matrices utilities, Basic calculations. When to start using
Mata over Stata?‏
Hi all,
I have a total of 20 matrices, A1-A10 and B1-B10 of size
25x36
I am trying to do the sum of each row of the matrix A and
compare them with the sum of each row of the matrix B. Then I retain the
highest sum and put it in a new matrix, say C.
The "rowsum" utility in Mata is appealing, but I couldn't figure out how to
create
the loops ( no "foreach" command?), generate new matrixes names
automatically (for the matrices C) and access my 20 matrices within the
loops in Mata.
Here is what I would do if I could use "rowsum"
in Stata:
foreach n in 1 2 3 4 5 6 7 8 9 10 {;
matrix c'n´= J(rowsof(A'n´),1,0) *I create my matrix c (vector of
25 rows) containing only 0 values ;
foreach i in 1-25 {;
* where i correspond to the number of rows;
R_sum_A'n´=rowsum(A'n´) ;
R_sum_B'n´=rowsum(B'n´) ;
*I compare the two sums and if the rowsum of A is bigger than B I
put it in the new matric C, if not I leave it equals to 0 ;
if el(R_sum_A'n´,'i´,1)> el(R_sum_B'n´,'i´,1)
matrix C'n´['i´,1] =el(R_sum_A'n´,'i´,1) ;
};
};
But I cannot use "rowsum" into stata . So what would you suggest ?
Thanks a lot
Raphael
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